The main reason for the difficulties in demonstrating an impact on fracture incidence in these long-term studies is the

absence of a placebo control. One solution is to compare fracture incidence with the first years of the study, in which selleckchem efficacy versus placebo has already been demonstrated. Thus, the 8-year pooled analysis of SOTI and TROPOS reported no statistical PF-4708671 cell line difference between incidence of fracture in the first 3 years of the trials (years 0 to 3) and the first 3 years of the extension (years 6 to 8) for vertebral, nonvertebral, or any osteoporotic fracture [13]. Our finding of similar rates in the first 5 years (years 0 to 5) and the last 5 years (years 6 to 10) reinforces the conclusion that the antifracture efficacy of strontium ranelate is sustained in the long-term. However, we also compared these cumulative incidences with those in a FRAX®-matched placebo population in the TROPOS study in an exploratory post hoc analysis. The advantage of FRAX® is that it provides estimates of 10-year fracture risk [16, 17], presenting the opportunity to identify patients at the same level of risk at the beginning of a 5-year observation period, as the 10-year population at year 5, reducing confounders such as aging of the population, prevalent fracture, and other risk factors. We used FRAX® scores calculated without BMD in patients already treated with strontium ranelate

for 5 years, precluding GSK1838705A any potential bias related to the effect of treatment on BMD. On the other hand, FRAX® does not account for the number MycoClean Mycoplasma Removal Kit and severity of prevalent fractures, which is a limitation of the tool. Our results of lower rates of fracture in the patients between 5 and 10 years of treatment versus this matched placebo group strongly support sustained long-term

antifracture efficacy of strontium ranelate over 10 years. Our observation of a similar efficacy between 6 and 10 years as in the first 5 years of treatment is also in line with the reported absence of influence of age, baseline BMD, or other risk factors on the efficacy of strontium ranelate [11]. Moreover, a recent analysis by Kanis confirmed that the efficacy of strontium ranelate in clinical and morphometric fracture did not depend on baseline fracture risk assessed by FRAX® [20], whereas the same analyses performed with antiresorptive agents such as denosumab [21] and clodronate [22] indicated efficacy against clinical osteoporotic fracture in patients at moderate and/or high risk only. The levels of compliance with strontium ranelate over 10 years compare well with those reported in the long-term studies with alendronate [2, 23], even considering the design of this extension study, in which the patients themselves chose to continue treatment. Our study has the limitations of many long-term trials in the management of a chronic disease (absence of comparator, small sample size, and open-label design).